1. Field of the Invention
The present invention relates to a printer, a print control program, a medium having print control program recorded therein, and a printing method.
2. Description of the Prior Art
How humans perceive colors from ink attached to printing paper may be explained in terms of the product of three factors—the spectral distribution of the light source, the reflectance of the ink and printing paper, and the color matching function which depends on the characteristic properties of the human eye. Printers usually produce colors by combination of three inks expressing C (cyan), M (magenta), and Y (yellow) [the former two may be replaced by lc (light cyan) and lm (light magenta), respectively, which are similar to them in hue]. This means that the color humans perceive changes as ink changes in its spectral distribution. An adequate combination of colors (C, M, Y) produces an achromatic color (gray) on printing paper.
Printing with a conventional printer needs preliminary steps. First, trial print undergoes colorimetry with a specific light source. Then, a correspondence between ink combination and image data is established on the basis of calorimetric values. Finally, regular printing starts while referencing the correspondence. Since any color is represented by the product of three factors as mentioned above, it is essential that the colorimetry be carried out under a specific light source. If a printed product is observed under a light source which is different from that used for the colorimetry, then it looks differently. This phenomenon occurs remarkably in the case of low chromatic color or achromatic color (gray). For example, an object which takes on gray under the sunlight would look reddish under the room light. Pigment-based ink greatly varies in hue depending on light sources.